Not possible to export if some assets are missing

[bobpaul]

It's currently not possible to export if some assets are missing. Games are often still playable with a few missing assets (esp if the missing asset is something like an instruction manual PDF).

I propose that this gets added as behavior to the "-f, --force" option.

It'd be nice if the export was somehow marked as incomplete, but it's just a zip file with .pak as the file extension. Any thoughts on this? We could include a list of missing assets as a text file in the PAK, or put the word incomplete in the default file name or something.

[bobpaul]

Normal PKZip comment text is something like {"Ver": 1, "Id": "779344331", "Type": "workshop"} Perhaps add something to this? A missing file count?

[cwoac]

It's probably a good idea to add; for the purposes of #27, I've labelled partials as .part.pak rather than .pak. Adding some form of indication as to what is missing is worth doing.
I'm uncertain on what amount of space we have in a comment, so perhaps a missing.txt might be more appropriate?

[bobpaul]

Hmm, good call. Looks like zips use 2 bytes for comment length, so I think max is 65535bytes. And putting that information in a separate file is more visible to someone who might open the file and try to extract things manually.

BUT Thinking about this a bit more, how useful is a list of missing URLs really? All of the URLs are already in the json file, afterall. I could see us generating this file but then never using it, and if that's what we expect then it's probably not worth generating the file.